chore(CPlusPlus): add moore voting algo (#268)

algorithms/CPlusPlus/Arrays/boyer_more.cpp

@@ -0,0 +1,66 @@
+//majority element of an array 
+// element with frequency > (n/2) {n: size of array}
+//time complexity : O(n) || space complexity : O(1)
+
+#include<iostream>
+
+using namespace std;
+
+void ismaj(int arr[],int n,int exp_maj){ // checks the if the candidate element is actually the majority element or not
+
+    int i=0;
+    int count =0;
+    for(i=0;i<n;i++){
+        if(arr[i]==arr[exp_maj]){
+            count++;
+        }
+    }
+
+    if(count>(n/2)){
+        cout<<"majority element : "<<arr[exp_maj];
+    }
+    else{
+        cout<<"no majority element found\n";
+    }
+}
+
+
+int majelement(int arr[],int n){ // majority element function to find the candidate majority element 
+
+     int ans_index=0; // setting ans_index initially as the first element
+     int count =1; // setting count of first element as 1
+
+    for(int i=0;i<n;i++){
+        if(arr[i]==arr[ans_index]){
+            count++;
+        }
+        else{
+            count--;
+        }
+
+        if(count ==0){ 
+            ans_index=i; // updating ans_index as the ith element
+            count =1; // resetting count
+         }
+    }
+
+    return ans_index;// expected majority element
+} 
+
+
+int main(){ // main function begins here
+    int size;
+    cout<<"enter the size of the array : ";
+    cin>>size;
+
+    int *arr = new int[size];
+
+    for(int i=0;i<size;i++){
+        cout<<"enter "<<i<<" th element of array : ";
+        cin>>arr[i];
+    }
+
+    int result = majelement(arr,size);
+    ismaj(arr,size,result);
+    return 0;
+}

algorithms/CPlusPlus/README.md

@@ -6,6 +6,7 @@
 3. [Left Rotation](Arrays/left-rotation.cpp)
 4. [Max Subarray Sum](Arrays/max-subarray-sum.cpp)
 5. [Shift Negatives](Arrays/shift-negatives.cpp)
+6. [Boyer–Moore Voting Algorithm](Arrays/boyer_more.cpp)
 
 ## Graphs
 1. [Bellman Ford Algorithm](Graphs/bellmam-ford.cpp)